Valve

ABSTRACT

A valve comprises a valve housing (2) with a valve inlet (11), a valve outlet (12) and a passage (66) extending through the valve housing (2) from the valve inlet (11) to the valve outlet (12). A valve seat (5) is provided in the passage which comprises a valve sealing surface (50). Further, the valve comprises a blocking element (3) adapted to be moved at least partly into the valve seat (5) for blocking the passage by abutment on the valve sealing surface (50), the blocking element being moved along a direction (102) extending under an acute angle to the plane (90) in which the valve seat (5) is arranged. The valve sealing surface (50) of the valve seat (5) is spherical in shape.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/EP97/05050 which has an Internationalfiling date of Sep. 16, 1997 which designated the United States ofAmerica.

BACKGROUND OF THE INVENTION

The invention refers to a slanted seat valve with a valve inlet, a valveoutlet and a passage extending through the valve housing between thevalve inlet and the valve outlet.

Valves are often used to block pipe lines against media flowing therein,which valves are, in particular, stroke valves with a conical seatsurface and a blocking element fixed at a spindle and displacedvertically to the flow direction when the valve is closed. Such valvesare disadvantageous because of their high drag and the resulting greatflow losses occurring in the closing area due to the deflection of theflow.

Slanted seat valves represent a development of these straight seatvalves; here, the valve seat is a slanted portion of a circular cone,the symmetrical axis of which extends in parallel to the spindle axis. Aslanted arrangement of the valve seat and the blocking element may welleffect a reduction of the drag, but in case of a spindle arrangedobliquely with respect to the pipe axis, this valve is disadvantageousbecause of a larger stroke and an impaired operability resultingtherefrom. With slanted seat valves having the spindle axis and the pipeaxis arranged at right angles, larger pressure differences between theblocking element sides, due to the imbalanced distribution of surfacepressure, will cause leaks at the valve seat, since the required surfacepressure doses not prevail everywhere. With such slanted seat valves, aneccentric arrangement of the blocking element at the spindle requires anadditional fixing against rotation using fixing elements such as pins.

From DE-A-43 42 025 und DE-A-36 09 772, slanted seat valves optimizedwith respect to the sealing problems are known. The balancing of thesurface pressure caused by the force of the spindle over the valve seatsurface is achieved by disposing the spindle axis connected with theblocking member eccentrically relative to the center of the plane formedby the valve seat surface and projected in the direction of the spindleaxis. The spindle axis is shifted towards a (top) portion of theblocking element proximal to the spindle, the point of attack of thespindle force being arranged such that its effective directionintersects the perpendicular lines to the valve seat surfaces in theintersection of the center plane of the blocking element and the valveseat surface and the pressure component vertically attacking theblocking element within a triangle formed by these intersecting straightlines.

A study of the force relations at the blocking element reveals thatthere is a limit pressure difference Δp_(G) in this embodiment as well,at which the limit pressure force F_(pG) is canceled at one point of thesealing surface so that leaks can occur. Increasing the spindle forcemay result in a limited improvement; however, the increase of thespindle force is limited by the strength of the spindle and the valvehousing.

Further possibilities to increase the limit pressure force F_(pG) areknown, using, on the one hand, valves having a very steeply inclined,almost vertical valve seat or, on the other hand, valves having aconical valve seat, the cone axis being inclined towards the spindleaxis. A steeply inclined seat surface is disadvantageous in that, uponopening the valve, the valve plate may jam due to some self-lockingeffect and cannot be opened without damage. In the slanted embodiment ofthe conical seat only very shallow elliptic flow cross sections areachieved so that the drag is rather great in these valves.

From DE-A-24 30 537, a slanted seat valve with a wedge-shaped blockingelement is known that is movable transversely into the passage of avalve housing. The oblique face of the blocking element seals against avalve seat formed in the passage and having a continuous bead shapedvalve sealing surface. The valve housing comprises guides for the wedgeshaped blocking element, thereby preventing that the blocking elementcannot be deflected in the direction of the length of the passage whenbeing pressed against the valve sealing surface. This adds to themachining effort for the valve housing and increases the costs for thevalve.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a valve, in particular aslanted seat valve that reliably seals the passage of the valve housingwhile being of a most simple structure.

The object is solved according to the invention by providing a valvecomprising

a valve housing with a valve inlet, a valve outlet and a passageextending through the valve housing from the valve inlet to the valveoutlet,

a valve seat provided in the passage and comprising a valve sealingsurface, and

a blocking element adapted to be moved at least partly into the valveseat for blocking the passage by abutment on the valve sealing surface,the blocking element being moved along a direction extending under anacute angle to the plane in which the valve seat is arranged.

This valve is characterized according to the invention in that the valvesealing surface of the valve seat being spherical in shape.

This spherical shape of the valve sealing surface of the valve seatcauses a linear contact between the blocking element and the valve seat.The fact that the blocking element may be moved at least partly into thevalve seat for blocking the passage by linear abutment on the bulbous,spherical or convex valve sealing surface, thus at least partlypenetrating the valve seat in the blocking state, the valve seat isundercut und thereby sealed reliably since the prevailing pressure isconverted into a pressure force pushing the blocking element furtherinto the valve seat.

According to an advantageous development of the invention it is providedthat the valve sealing surface of the valve seat lies on a (imaginary)annular member and forms a part of the surface thereof. This annularmember comprises a central plane on which the central axis of theannular member stands. Since the valve sealing surface is formed bysurface portions of the annular member located above and below thiscentral plane, the plane of the valve seat and the central plane extendunder an acute angle of inclination, in particular an angle between 10°and 30°, and preferably about 20°.

In other words, the annular member comprises a bottom face directedtowards the valve inlet and a top face directed towards the valveoutlet. Here, the valve sealing surface is formed by parts of thesurface of the imaginary annular member located in part on the top faceand the bottom face, respectively, and, again in part, on the level ofthe central plane on the inner surface of the annular member between thetop and the bottom faces thereof.

Preferably, the annular member is a circular or oval annular member, inparticular having a circular or otherwise round cross section. The areaenclosed by the annular member, seen in projection of the direction ofmovement of the blocking element, is equal to the cross-sectional areaof the blocking element. At the level of these two areas, the exteriorof the blocking element and the inner surface of the annular member arein contact along a sealing line. Such linear pressure is easier torealize with high pressure forces than surface pressure, which is whythe present valve has reliable sealing properties while being of mostsimple structure.

In an advantageous embodiment of the present invention, the direction ofmovement of the blocking element extends substantially rectangular tothe extension of the passage. In addition, it may suitably provided thatthe plane in which the annular member is located extends under an acuteangle of inclination of the annular member to the extension of thepassage. This angle of inclination is preferably between 30° and 60°, inparticular between 40° and 50°, and preferably substantially about 45°.

Preferably, the blocking element is a pointed, blunt or beveled cone,whereas the imaginary annular member is an oval ring with a circularcross section inclined such with respect to the direction of movement ofthe blocking element that it encloses a circular area, seen in thedirection of movement of the blocking element.

According to an advantageous embodiment of the invention, it is providedthat the valve seat is an integral part of the valve housing and is madewhen forming the valve housing. As an alternative, it may be providedthat the valve seat is a separate member inserted into the valvehousing.

Further, it is provided according to an advantageous embodiment of theinvention that the valve housing is in the shape of a T-pipe with asubstantially straight passage pipe portion and a branch pipe portionsubstantially rectangular to the same. The blocking element is situatedin the branch pipe portion and is moved into the passage pipe portionfrom the side. The inner surface of the passage pipe portion is formedwith an inward protruding continuous annular surface extending into thepassage pipe portion as a projecting bead. This annular projecting beadis situated under an angle of 45° to the longitudinal axis of thepassage pipe portion and, thus, also forms an angle of 45° with thelongitudinal axis of the branch pipe portion. The center of the areaenclosed by the annular projecting bead coincides with the intersectionof the longitudinal axes of the passage and branch pipe portions. Thismeans that the annular projecting bead extends in the corner portionbetween the passage pipe portion and the branch pipe portion.

A valve housing formed according to the above described specification isadvantageous in that straight-way valves and corner valves may beproduced using the same valve housing. With a straight-way valve, theblocking element and the moving element moving the same are situated inthe branch pipe portion so as to be moved into the passage pipe portion.Using the valve housing for a corner valve, the blocking element issituated in one portion of the passage pipe portion and may be movedinto the other portion of the passage pipe portion to block the angledpassage between this portion of the passage pipe portion and the branchpipe portion. Whereas, in the straight-way valve, the inlets and outletsof the valve housing are formed by the axial end of the passage pipeportions, the inlets and outlets of the valve housing of a corner valveare formed by one of the two axial ends of the passage pipe portion andby the axial end of the branch pipe portion.

The annular bead-like projection on the inner surface of the passagepipe portion is preferably formed by a local beading deformation in thewall of the T-pipe. With such a valve housing, the exterior thus has acontinuous depression inclined under an angle of 45° to the longitudinalaxis of the passage pipe portion and the longitudinal axis of the branchpipe portion. The valve housing is advantageously made from plasticsmaterial. Injection molding or high pressure forming are suitablemanufacturing methods, where, in the latter, a blank is given thedesired shape by creating high internal and/or external pressures. Bothmethods are advantageous in that the inner side of the passage pipeportion, and thus the valve seat and its valve sealing surface, need notbe machined afterwards but may be manufactured directly together withthe valve housing.

The present invention comprises a valve housing with a valve seat havinga three-dimensional convexly curved seat surface as the valve seatsurface. In the closed position of the valve, a blocking element engagesthe valve seat positively and non-positively, the blocking element beingprovided in particular at the end of a spindle or another movingelement.

The valve sealing surface lies on a surface section of an imaginaryannular member annularly extending around the valve seat, the annularmember being created by rotating a (cross-sectional) area on a circularor elliptic path lying in a plane of rotation about a central axissituated in the sectional area of flow of the valve seat or by rotationabout this central axis. The cross-sectional area is convex at the edgefacing the central axis so that the tangent lines to annular membercircumference points proximal to the central axis extend almost parallelto the central axis and the tangent line to lower or upper annularmember circumference points more distant from the plane of rotation arealmost parallel to the plane of rotation. Feasiblely, thecross-sectional areas of the annular member are circular or ellipticareas or areas partly defined by parabolic or hyperbolic lines.Similarly, areas formed by a polygon, whose circumferential portiondistant from the plane of rotation is formed by a straight line slightlyinclined with respect to the plane of rotation, the circumferentialportion close to the central axis being formed by a section of a circleand the circumferential portion close to the plane of rotation beingformed by a straight line steeply inclined with respect to the plane ofrotation.

In a particularly preferred embodiment, the imaginary annular member hasa toroidal surface, the annular member being inclined under an acuteangle α (angle of inclination of the annular member) with respect to themain flow direction, or the pipe axis, extending between the valve inletand the valve outlet. Suitably, the blocking member is frustoconical,presenting linear contact with the valve sealing surface (torus) of thevalve seat when in the closed position. Compared to surface contact, alinear contact has a much higher surface pressure and the seat surfaceis less sensitive to impurities due to the small contact area.

The sealing line corresponds to a generating line around the torus, onwhich line a first (upper) generating line point close to the spindleand a second (lower) generating line point distant from the spindle areprovided. In vertical section, the annular member has a first (upper)cross-sectional area and a second (lower) cross-sectional area. Thefirst generating line point lies on a portion of a first circumferenceof the upper cross-sectional area, the portion extending between a firstintersection and a first tangential point, the first intersection beinga spindle-side (upper) intersection of a first diameter of the uppercross-sectional area, extending in the effective direction of a pressureforce attacking at the inflow-side of the blocking element, with thefirst circumference, and the first tangential point being a firstcontact point of a tangent to the inner convex surface, the tangent lineextending in parallel with the spindle axis. The second generating linepoint lies on a portion of a second circumference of the lowercross-sectional area, the portion connecting a second intersection and asecond tangential point, the second intersection being an intersection,inside the convex surface, of a second diameter of the lowercross-sectional area lying in the plane of rotation with the secondcircumference, and the second tangential point being a second contactpoint of a tangent line to the inner convex surface extending inparallel with the spindle axis.

With such an arrangement of the valve seat and the valve plate, theblocking element, when in the closed position of the valve, undercutsthe valve seat in the lower portion of the valve seat in the directionof the pressure force F_(p) caused by the pressure difference so thatthe fitting is self-sealing in this portion. The pressure force F_(p)does not urge the top portion of the blocking element away from thevalve seat, since the entire blocking element is supported in the lowerportion of the valve at the spindle guide perpendicular to the spindleaxis. Thus, the blocking element is stable without any active force inthe axial direction of the spindle. An active spindle force F_(s) wouldbe distributed over the entire sealing surface without an additionalpressure force taking influence on the resulting surface pressurebetween valve seat and blocking element.

A study of the forces attacking at the blocking element reveals that,ideally, the sealing line extends between the first (upper) tangentialpoint and the second (lower) tangent line point of the twocross-sectional areas.

A disc-like valve plate with a concave plate edge surface as the valveplate sealing face, which, in the closed position, abuts the valve seatpositively and non-positively and whose in-flow valve plate front sideis arranged under an acute angle β (inclination angle of the plate) tothe plane of rotation of the imaginary annular member, is also suited asthe blocking element. The contour of the valve plate is designed suchthat, in the closed position of the valve, the valve plate front side isdefined by a sealing edge (sealing line) terminating the sealingsurface.

Together with the frictional forces acting on the sealing surface, ashifting of the spindle axis towards the upper generating line point hasa positive effect on the compensation of the moments generated in theupper portion of the sealing surface.

The present shapes of the blocking element allow for a smooth insertionof the blocking element into the valve seat form the side of the movingelement, in particular from the spindle side, the blocking elementsealing tightly at any point of the valve seat, when closed. Theinclination of the imaginary annular member causes the drag in the valveto decrease, since circular or elliptic sectional areas of flow areobtained. The curved surface of the imaginary annular member enhancesthe flow through the valve, i,e. The drag is small.

Another advantage lies with the self-centering of the valve plate in thevalve seat, since the forces in the lower portion of the valve plate arealways strong enough to overcome the counteracting friction forces inthe upper portion of the seat surface and to thereby cause the valveplate into an optimum position.

Summarizing, it is to be noted that a much better sealing is obtainedwith a bulbous, spherical, convex valve seat surface, in particular apartial surface of a torus, than with a stroke valve having a conicalvalve seat surface. Further, it is possible to design a housing passagewith enhanced flow properties having an approximately constant circularpassage section.

Thus, the invention refers to a valve with a valve housing having anin-flow valve inlet and an out-flow valve outlet. The valve housing isprovided with a valve seat and a blocking element arranged at the end ofa spindle, the blocking element abutting positively and non-positivelyat a valve sealing surface of the valve seat, when in the closedposition. The valve seat has a three-dimensional convex seat surface asthe valve sealing surface. In other words, the valve sealing surfacelies on the surface of an imaginary member (annular member) with acentral axis and extending annularly about the valve seat. This isinclined under an acute angle α (angle of inclination of the annularmember) to the main flow direction between the valve inlet and the valveoutlet. The surface of the annular member suitably is a torus.

In an advantageous embodiment of the invention, the spindle is displacedvertically along the spindle axis, i.e. rectangular to the main flowdirection along a pipe axis, wherein, in the closed position of thevalve, the blocking element has at least a linear contact with the valvesealing surface of the valve seat and abuts a generating line around aninner convex surface of the annular member with at least one sealingline, a first generating line point close to the spindle and a secondgenerating line point distant from the spindle being situated on thegenerating line. The first generating line point lies on a portion of afirst circumference of a first cross-sectional area of the annular body,the portion extending between a first intersection and a firsttangential point, the first intersection being a spindle-sideintersection of a first diameter of the first cross-sectional area,extending in the effective direction of a pressure force F_(p), with thefirst circumference, and the first tangential point being a firstcontact point of a first tangent to the inner convex surface, thetangent line extending in parallel with the spindle axis. The secondgenerating line point lies on a portion of a second circumference of asecond cross-sectional area of the annular member, the portionconnecting a second intersection and a second tangential point, thesecond intersection being an intersection, inside the convex surface, ofa second diameter of the lower cross-sectional area lying in the centralplane with the second circumference, and the second tangential pointbeing a contact point of a second tangent line to the inner convexsurface extending in parallel with the spindle axis, the pressure forceF_(p) attacking in the direction of the normal at an inflow-side frontof the blocking element and being caused by a pressure difference Δpbetween the valve inlet (11) and the valve outlet (12).

Preferably, the blocking element is a cone or a truncated cone with theblocking element having a convex outer shape in particular on theclosing side.

As an alternative, the blocking element is formed on the closing side bya disc-like valve plate with a concave plate edge face as the valveplate sealing surface, the sealing line being a sealing edge of thevalve plate sealing surface located on the inflow side, the valve platesealing surface defining an inflow-side valve plate side (valve platefront side) so that the valve plate front side is inclined under anacute angle β (plate inclination angle) to a plane of rotation of theannular member, the plane standing rectangularly on the axis ofrotation. Advantageously, it is provided that the sealing line and/orthe sealing edge abut the generating line extending around a convexinner surface of the annular member, the line extending between thefirst generating line point close to the spindle and the secondgenerating line point distant from the spindle, where the firstgenerating line point is the first tangential point und the secondgenerating line point is the second tangential point.

Preferably, the spindle axis is shifted from the center, and,preferably, it is shifted towards the first generating line point.

It is another aspect of the invention to provide a method formanufacturing a fitting, in particular for a slanted seat valve having,in particular, a toroidal seat surface, by which method the fittinghousing may be fabricated in short manufacturing periods (cycle times)with a complex geometry, at low cost and in simple manner, and whichallows for a high reproduction rate within a narrow tolerance range.

Until now, fittings and valves have been made using a combination offorming or reforming and machining methods so that the valve seat mustbe formed later. These conventional manufacturing methods are timeconsuming and costly, which is due, among other reasons, to the highnumber of process steps and, in particular, to the ulterior machining ofthe valve seat contour.

The present valve may be made in a simple manner by manufacturing a pipewith a predetermined diameter, which serves as the blank, into a fittinghousing by a non-cutting forming process, the housing being a finishedpart with a spatially convex fitting seat surface as one fitting sealingsurface.

The preferred method of production is high-pressure forming method(HPF), wherein the fitting housing is given its final shape in aplurality of method steps. Using the present method, one may alsoproduce valve housings with a slanted valve seat having athree-dimensionally convex valve seat surface.

The inner diameter of a blank pipe corresponds to the nominal width ofthe fitting. The high-pressure forming method can work blanks with awall thickness s between 1.0 and 10.0 mm, while pipes with wallthicknesses up to 25.0 mm may be used if the pipes are made of aluminum.

It is another advantage of this method that the pipe of the valve hasalmost the original wall thickness of the blank even in the formed areaand that the wall thickness may be variably adjusted in the region ofthe seat depending on the predetermined elasticity of the seat.

With a variable process control of the high-pressure forming (HPF), thewall thickness can be varied so that the valve seat surface may bedesigned as an annular spring in the region of the valve seat surface,whereby manufacturing and operation tolerances are compensatedelastically.

In high-pressure forming, a dimensional stability of the parts isprovided only at the forming side of the tool, i.e. the non-pressurizedside of the part surface. The dimensional stability of the valve seat isinfluenced substantially by the effective forming pressure p_(i) orp_(a) and the diameter ratio of the outer diameter of the die to theinner diameter of the pipe, the ratio being larger than 1. Thetolerances for the surface facing the tool, i.e. the non-pressurizedside of the finished part, are very small in high-pressure forming(HPF). Moreover, a very precise reproducibility within a narrowtolerance range are obtained.

Further, high-pressure forming (HPF) allows to form finished housingsfrom any deformable (ductile) material.

It is another advantage that the high strain caused by deformationcauses a workhardening in the area of the valve seat, the greaterstrength protecting the valve seat against wear.

Since, according to the preferred method for manufacturing the presentvalve, the sealing surface requires no posterior treatment and possibleconnections may be formed directly to the housing, valve housings can bemade in very short production cycles, with optimum use of the materialand minimum cutting (production of the valve plate). The productioncycle for manufacturing a fitting housing is less than 3 minutes in athree-step HPF method. Using high-pressure forming (HPF) allows for verysmooth surfaces by leveling the irregularities (peaks), resulting in apositive effect on the efficiency of the open fitting, because of thedecreased drag.

With a valve having a blocking element with a concave sealing surface,the shape of the valve plate and possibly the valve seat is formed witha CNC milling machine and a form milling machine. A fine treatment mayalso be performed, if necessary.

The spindle is positioned when the blocking element is set into thevalve seat, i.e. in the potential closed position of the valve. To dothis, a bore (receiving opening) for positionally fixing the spindle atthe blocking member is drilled only when the latter is in position, orthe spindle is positioned into and adjusted in an existing bore of theblocking element.

The above described method for forming a fitting with a fitting housingand a blocking element arranged therein is characterized in that a pipemember serving as a blank and having a predetermined pipe inner diameterd_(R),i is worked by non-cutting forming into a fitting housing formingthe finished part and having a spatially convex fitting seat surface asa fitting sealing surface. Here, the fitting housing is given itsfinished part shape preferably in a plurality of steps by ahigh-pressure forming process.

In an advantageous development, the method provides, when forming theblank into the finished part, the wall thickness of the blank ispreserved, the fitting housing having approximately the original wallthickness of the blank even in the formed portion and the wall thicknessbeing variably adjustable in the seat area depending on thepredetermined elasticity of the seat.

The deforming of the blank preferably brings about a resilient fittingseat surface, in particular in the form of an annular spring.

The fitting manufactured according to the above described method is astroke valve with a valve housing and a slanted valve seat.Advantageously, in a first method step for roughly forming the outercontour of the valve housing, the blank situated in a single- ormulti-part tool form is widened into a T-shaped member with a passageportion and a branch (T-portion) closed at the end, wherein, after theclosing of the tool form, the blank is compressed by the forming forcesgenerated at the end faces of the blanks by pressing dies, and aninternal pressure p_(i) simultaneously presses the blank into an openingprovided in the tool for forming the T-portion. Subsequently, the valvehousing is given its finished part contour in a second method step, bypenetrating the T-shaped member transversely to the longitudinaldirection of the passage in the region of the branch, using a tool die,and cutting the closed end (cover) off the branch of the T-shapedmember, and in a third method step for forming the interior in theregion of the penetration, a valve seat contour is formed before thebranch by an external high pressure P_(a) applied to the outside of theT-shaped member using inner contour forming dies that are inserted asinternal tools into the branch of the penetrated T-shaped member andinto open end portions of the passage portion.

Advantageously, in shaping the inner contour, a valve seat is formedusing the inner contour forming dies in the region of the penetrationand in the longitudinal direction before the branch of the penetratedT-shaped member, the valve sealing surface lies on the surface of animaginary annular member extending around the valve seat and obliquelyto the branch.

Suitably, the blank has wall thickness between 1 and 10 mm; preferably,the diameter ratio of the die outer diameter d_(s),a of the innercontour forming die and the pipe inner diameter d_(R),i of the blank islarger than one.

BRIEF DESCRIPION OF THE DRAWINGS

The following is a detailed description of preferred embodiments of theinvention with reference to the drawings. In the Figures:

FIG. 1 is a sectional view of a slanted seat valve with a toroidal valveseat and a valve plate in vertical section,

FIG. 2a is a perspective view of another embodiment of a slanted seatvalve with a toroidal valve seat and a valve plate in vertical section,

FIG. 2b is a side elevational view of a slanted seat valve with atoroidal valve seat and a conical blocking element in section,

FIG. 3 is a side elevational view of the blocking element in FIG. 2,

FIG. 4 is a schematic side elevational view of the stroke valve of FIG.2 in vertical section,

FIG. 5 is a schematic side elevational view of the stroke valve of FIG.2 in vertical section, with a diagram of the forces acting on theblocking element,

FIG. 6a illustrates a first method step of a HPF process, wherein ablank is widened into a T-shaped member,

FIG. 6b illustrates a second method step of the HPF process, wherein theT-shaped member is penetrated and the closed end of the T-shaped memberis cut off,

FIG. 6c illustrates a third method step of the HPF method, wherein thepenetrated T-shaped member is provided with the valve contour,

FIGS. 7 and 8 illustrate another embodiment of the invention in the formof a straight-way valve in the closed position (FIG. 7) and in the openposition (FIG. 8),

FIGS. 9 and 10 illustrate an embodiment of the invention in the form ofa corner valve in the closed position (FIG. 9) and in the open position(FIG. 10), the valve housing being identical to the valve housing of thevalve in FIGS. 7 and 8, and

FIGS. 11 to 13 are partial longitudinal sections of further embodimentsof the present valve for illustrating different possible designs of thevalve sealing surface.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments of a slanted seat valve 1, illustrated in FIGS. 1 to 5,comprise a valve housing 2 with a valve seat 5, an inflow-side valveinlet 11 and an outflow-side valve outlet 12 that may be blocked againstthe flowing medium by a blocking element 3 fixed at the end of a spindle4 disposed in the housing 2. In the embodiments illustrated, the spindle4 is displaced along its spindle axis SA rectangularly to the flowdirection SR or the pipe axis. In the closed position of the valve 1,the blocking element 3 abuts a bulbous, spherical or convex bulgingvalve sealing surface 50 of the valve seat 5, which lies on an imaginaryannular member RK extending around the valve seat 5 and having a torus 6as the surface.

The positions given for the points MP1, MP2, SP1, SP2, TP1, TP2, and thesections U1, U2, QF1, QF2 on the torus 6 refer to an imaginarycoordinate system with its origin in the center of the torus 6 and theaxes of which lie on the central axis RA and the plane of rotation orcentral plane RE of the annular member RK, where "top" and "bottom"describe the position of a valve 1 with an upward spindle extension asillustrated in FIGS. 1, 2a and 2b, 4 and 5.

The torus 6 is inclined under an acute angle α (annular memberinclination angle) in the direction of the main flow direction SRextending between the valve inlet 11 and the valve outlet 12.

The annular member inclination angle α enclosed by the main flowdirection SR and the central plane RE of the torus 6 has a value of 0°to 90°, in particular 30° to 60° and preferably 40° to 50° so that thesectional area of flow has a circular or elliptic shape in the closingregion of the blocking element 3.

The blocking element 3 may be a valve plate 31 with a concave plate edgesurface as the generated surface 30 (see FIG. 2a) or a truncated cone 3a(see FIG. 2b) or, generally, an element with a concave generatedsurface. The contour of the blocking element 3 is designed such that, inthe closed position, its generated surface 30 abuts a generating line 63along at least one sealing line 33, the generating line extending alongthe inner generated surface 61 of the annular member 6, on whichgenerated line a first (top) tangential point TP1 close to the spindleis provided as a first generating line point MP1 and a second (bottom)tangential point TP2 distant from the spindle is provided as a secondgenerating line point MP2.

In the closed position of the valve 1, a component of the pressure forceF_(p), extending in the direction of the normal to an inflow-side frontface of the blocking element 32, attacks at the blocking element 31,this pressure force F_(p) resulting from the pressure difference Δpbetween the front face 32 or the valve inlet 11 and the outflow-siderear face 36 of the blocking element or the valve outlet 12.

FIG. 1 illustrates a slanted seat valve 1 with a valve seat 5, in whichthe valve inlet 11 and the valve outlet 12 lie on an axis extending inthe flow direction SR, the clear passage of which corresponds to thenominal width in the closing region of the blocking element 3. The valveseat 5 comprises a valve sealing surface 50 that corresponds to a partof the toroidal surface.

The rear face 36 of the blocking element is adapted to the valve housing2 so that the rear face 36 abuts positively on the inner wall of thehousing, when the valve 1 is open.

The blocking element 3 is reinforced in the region of the receivingopening 34 for the spindle 4, i.e. the shape passes from a disk-likeplate form into a compact block 35 including the receiving opening 34.

FIG. 2a illustrates an embodiment of a slanted seat valve 1 with atoroidal valve seat 5, in which the open diameter is reduced in theclosing region of the blocking element 3, the valve inlet 11 and thevalve outlet 12 being disposed coaxially with respect to each other.

On the closing side, the blocking element 3 (see FIG. 3) is formed by adisk- and wedge-shaped valve plate, the concave plate edge surfaceforming the valve plate sealing surface (see surface 30 in FIG. 3). Inthe closed state, the valve plate with its circumferentially extendingsealing surface almost linearly abuts the top portion of the valve seat5 that is close to the spindle and presents a surface abutment at thebottom portion of the valve seat 5 distant from the spindle.

At the side of the spindle, the blocking element 3 has a reinforcement35 in the form of an arcuate extension member 35 forming a shaft forreceiving the spindle 4.

FIG. 2b also illustrates an embodiment of a slanted seat valve 1comprising a valve seat 5 corresponding to a part of a torus surface, asshown in FIG. 2a, yet, the blocking element 3 is formed by a truncatedcone 3a at the closing side. In the closed position, the blockingelement 3, 3a extends into the torus 6 and seals the valve 1 against theflowing medium along the sealing line 33 which is identical with thegenerating line 63 of the torus 6 forming the contact line 63.

FIG. 4 serves to explain the dependence of the contour of the valveplate 31 with a sealing surface 30 and the imaginary (toroidal) annularmember RK, 6, extending annularly bout the valve seat 5 of the housing2. The valve housing 2, having a wall thickness s with a constant valueover the entire cross section, is produced using a manufacturing methodfor making fitting housings, the method steps thereof being illustratedin FIGS. 6a to 6c. The valve plate front face 32 is inclined under anacute angle β (plate inclination angle) to the central plane RE of theannular member RK, 6.

In the closed position of the valve, the valve plate 31 abuts agenerating line 63 extending around a generated inner surface 61 of thetorus 6 with a front sealing edge 33 of the valve plate sealing surface30, a first top generating line point MP1 and a second bottom generatingline point MP2 being situated on this generating line 63.

In a vertical section through the valve 1, the entire sectional area ofthe annular member RK, 6 is formed by two circular surfaces (sectionalareas) QF1, QF2, the first sectional area QF1 being close to thespindle, that is above the centrals axis RA, and the second sectionalarea QF2 being distant from the central axis RA.

The first generating line point MP1 is located on a firstcircumferential portion U1 of the first top sectional area QF1 thatextends between a first intersection SP1 and a first tangential pointTP1. The first intersection SP1 is a spindle-side intersection SP1 of afirst diameter DM1 of the top sectional area QF1, extending in theeffective direction of the pressure force F_(p), and the circumferenceU1 thereof.

The first tangential point TP1 is a contact point of a tangent line TG1to the generated inner surface 61 of the upper torus portion in thefirst sectional area QF1, the tangent line extending in parallel withthe spindle axis SA.

The second generating line point MP2 lies on a second circumferentialportion U2 of the second, lower sectional area QF2, the portionconnecting a second intersection SP2 and a second tangential point TP2.

The second intersection SP2 is an intersection SP2, located on theinside of the generating line, of a second diameter of the lowersectional area QF2 situated in the central plane RE and thecircumference U2 thereof.

The second tangential point TP2 is a contact point of a tangent line TG2to the generated inner surface 61 of the lower torus portion in thesecond sectional area QF2, the tangent line extending in parallel withthe spindle axis SA.

The valve plate 31 undercuts the valve seat 5 in the lower portion inthe effective direction of the pressure force F_(p). In the upperportion of the valve seat 5, however, the valve plate 31 rests on thetop face of the seat surface 50.

The diagram of forces illustrated in FIG. 5 illustrates the interactionof the forces (F_(p), F_(s)) attacking at the valve seat 5 and thespindle 4 with the valve plate 31.

For a study of the force relations at the valve plate 31, the forcebehavior will be explained, for reasons of simplicity, with reference toa rigid bar, with frictional forces being neglected. The undercut of thevalve seat 5 by the valve plate 31 in the direction of the pressureforce F_(p) causes the blocking element 3 to be supported in the secondintersection SP2, presenting one bearing point, and to be supported atthe spindle guide 41 as a further bearing point C; thus, the forcesF₂,x, F₂,y und F_(c) are applied. The bearing force F_(c) is a reactionforce to the pressure force F_(p), directed axially to the spindle axisSA.

Since the pressure force F_(p) and the spindle axis SA are arrangedunder an acute angle to each other, the valve 5 is self-sealing, i.e.,the blocking element is supported in a stable manner in the axialdirection at the second intersection SP2 and the bearing point C withoutany effective spindle force F_(s).

In the portion of the sealing surface 30, 50, distant from the spindleand below the spindle axis SA, the pressure force F_(p) attacking at theblocking element 3 is in balance with the force components F₂,x and F₂,yin the second bearing point SP2 and with the bearing force F_(c) actingrectangularly on the spindle axis SA.

Since the valve plate 31 is supported in the lower portion of the valveseat 5 at the bearing point SP2 and at the spindle guide 41 at a rightangle to the spindle axis SA, the portion of the blocking element 3 thatis close to the spindle, is not pushed off the valve seat 5 by thepressure force F_(p) in the portion above the spindle axis SA.

An effective spindle force would be distributed evenly over theintersections SP1, SP2, without, upon an increase in pressure, anadditional pressure force F_(p) having any influence on the sealingbetween the valve seat sealing surface 50 and the valve plate sealingsurface 30 or the surface pressure resulting therefrom.

The present arrangement of the valve plate 31 allows for aself-centering of the plate 31, since the bearing forces F₂,x and F₂,yin the lower portion of the valve plate are sufficiently strong toovercome the opposing frictional forces and to push the plate into anoptimum position. The self-centering is enhanced by a larger torusdiameter, since in this case the valve seat sealing surface 50 forms amore acute angle with the spindle axis SA in the upper torus sectionQF1.

FIGS. 6a to 6c illustrate the method steps VS1, VS2, VS3 of a three-stepmanufacturing method for producing a slanted seat valve 1 with a(toroidal) valve seat surface as of FIG. 4.

When manufacturing a valve housing 2 according to the high-pressureforming method (HPF), it is provided in a first method step VS1 (seeFIG. 6a) for obtaining a rough outer contour of the valve housing 2, ablank R is widened into a T-shaped member TS with a passage portion TS1and a branch TS2 closed at the end. First, the blank R is placed into atool form W1 with one or a plurality of parts and presenting the outershape of the T-shaped member TS, and after closing the tool form W1, theblank is subsequently compressed by the forming forces F_(u) generatedat the end faces of the blank R by pressing dies DS1, DS2. Usingelongating and drawing processes and an externally generated internalpressure p_(i) applied to the blank R, the pipe material is pressed intoan opening WO formed in the tool for forming the transverse T-portionTS1, thereby obtaining the desired shape. A pressing die DS3 in the toolopening WO is a pressure pad DS1 acted upon by the force F_(G) andsupporting a uniform shaping of the branch TS2.

Preferably, longitudinally welded pipes are used as the blanks R.

To generate a sufficiently high internal pressure p_(i), the blank ispreferably filled with a non-compressible medium.

In a second method step VS2, the T-shaped member (TS) is penetratedtransversely to the longitudinal direction of the passage portion TS1 inthe area of the branch TS2 using a tool die WS2. The region of thepenetration D forms the basic form of the slanted valve seat 5. Theclosed end (cover) of the branch TS2 is cut off.

In a third method step VS3, using high-pressure forming, the contour ofthe valve seat 5 is shaped by the internally located tool IS1, IS2, IS3by applying an external high pressure p_(a) to the outside of theT-shaped member TS. To this avail, a three part tool IS1, IS2, IS3 isinserted into the branch TS2 and the open ended portions of the passageportion TS2. The pressure p_(a) on the exterior of the workpiece TS isgenerated by compressing an incompressible medium, the force beingapplied by dies arranged in pressure lines of the tool W3.

The following is a detailed description of further embodiments of theinvention made with reference to FIGS. 7 to 13. It is to be noted thatthe previously stated considerations concerning the force ratios an therelative arrangement of the individual components of the valve shouldalso be applied to the embodiments mentioned below.

FIGS. 7 to 10 are longitudinal sections of two embodiments 60, 60', bothvalves having the same valve housing 62. While the valve 60 is astraight-way valve, the valve 60' is designed as a corner valve.

The valve housing 62 of the valve 60, illustrated in FIG. 7 in theclosed position and in the open position in FIG. 8, comprises a T-shapedpipe member 64 consisting of a passage pipe portion 68 forming thepassage 66 and a branch pipe portion 70. The valve housing 62 is made ofplastics material. The opposite axial ends 72, 74 of the passage pipeportion 68 form the inlet 76 and the outlet 78, respectively, of thevalve 60. The branch pipe portion 70 is joined by a mounting means 80for a movement element in the form of a spindle 82 having one endprovided with a blocking element 84 in the form of a beveled truncatedcone. Turning the spindle 82 (the associated turning means is notillustrated in the FIGS. 7 to 10) moves the blocking member 84rectangularly into the passage 66.

In the passage 66, a valve seat 86 is formed that has a valve seatsurface 88. The valve seat surface 88 encloses a surface arranged in aplane 90 extending under an acute angle to the passage 66. The valveseat surface 88 is part of the surface of an imaginary annular member92, the central plane 94 of which extends under an acute angle to theplane 90. The central axis 96 of the annular member 92 extendsperpendicularly to the central plane 94. The annular member 92 forms anangle of about 45° with the longitudinal axis 98 of the passage 66. Thislongitudinal axis 98 intersects the intersection of the central plane 94with the central axis 96. The longitudinal axis 100 of the branch pipeportion 70 also passes through this intersection.

As illustrated in FIG. 7, the valve seat 86 is formed by a bead-likedeformation of the wall of the passage pipe portion 68. This bead-likedeformation causes an inward directed projection in the passage 66, thesurface of which corresponds to the inner surface of the ring. Theannular member 92 itself is of an oval shape. The main axes of this ovalare dimensioned relative to each other such that, seen in the directionof movement 102 of the blocking element 84, a circular inner surface isobtained into which the frustoconical blocking member 84 plunges toblock the passage 66.

In the blocking position of FIG. 7, the outer surface of the blockingelement 84 abuts the valve sealing surface 88 of the valve seat 86.Here, undercutting between the blocking member 84 and the valve seat 86occurs.

The advantage of the design of the valve housing 62 as illustrated inFIGS. 7 and 8 is that this valve housing 62 may be used both for thestraight-way valve 60 of FIGS. 7 and 8 and for the corner valve 60' ofFIGS. 9 and 10. The two variants use different surface portions of thevalve seat 86 for the sealing between the housing 62 and the blockingmember 84. In as far as the parts of the corner valve 60' correspond tothose of the straight-way valve 60 of FIGS. 7 and 8, they have beenaccorded the same reference numerals in FIGS. 9 and 10.

FIGS. 11 to 13 illustrate different embodiments of the design of thesealing surfaces between the valve seat and the blocking element. Alsoin these Figures, the parts corresponding to those of the valves 60 and60' of the FIGS. 7 to 10 are identified by the same reference numeralsin FIGS. 11 to 13.

As illustrated in FIG. 11, the sealing of the valve 60 is effected bymaking the valve housing 62 of plastics material. For manufacturingreasons (manufacturing the valve housing 62 as an injection moldedmember or by high-pressure forming, for example), a valve sealingsurface 88 is formed at the valve seat 86, the quality of the valvesealing surface being sufficient to directly cooperate with the outsideof the blocking element 84 so as to seal the valve 60. Instead ofplastics material, other material such as metal, for example, may beused.

In the embodiment of FIG. 12, the blocking element 84 is provided with amaterial coating 106 cooperating with the valve sealing surface 88 ofthe valve seat 86 to seal the valve 60. This material coating 106 may beelastically deformable. The housing 62 of the valve 60 of FIG. 12 ismade from metal or plastics material.

In the embodiment of FIG. 13, the housing 62 of the valve 60 is made ofmetal. The inner projection of the passage 66 forming the valve seat 86is provided with a receiving groove 108 inclined at about 45°, an ovalsealing member 110 of elastic plastics material being inserted therein.This oval annular member 110 provides for sealing together with theblocking element 84. Again, a sealing surface 88 forms on this annularmember 110, the sealing surface taking only a part of the surface of theannular member 110 and, as in the other embodiments of the valvesaccording to FIGS. 7 to 12, substantially linearly contacting theblocking element 84 and thereby sealing the valve 60.

What is claimed is:
 1. A valve comprisinga valve housing with a valveinlet, a valve outlet and a passage extending through the valve housingfrom the valve inlet to the valve outlet, a valve seat provided in thepassage and comprising a valve sealing surface, and a blocking elementadapted to be moved at least partly into the valve seat for blocking thepassage by abutment on the valve sealing surface, the blocking elementbeing moved along a direction extending under an acute angle to theplane in which the valve seat is arranged, whereinthe valve sealingsurface of the valve seat is bulbous in shape and forms a part of thesurface of an imaginary annular member, the annular member has a bottomface facing the valve inlet and a top face facing the valve outlet, andthe valve sealing surface is formed by parts of the surface of theimaginary annular member located in part on the top face and the bottomface, respectively, and, again in part, on the inner surface of theimaginary annular member between the top and the bottom faces thereof,the plane in which the valve seat is arranged, extends under an acuteangle to the plane in which the annular member is located, and theblocking element passes through the valve seat plane and the annularmember plane when in abutment on the valve seat surface.
 2. The valve ofclaim 1, wherein the angle is between 10° and 30°, preferably about 20°.3. The valve of claim 1, wherein the imaginary annular member is acircular, elliptic or oval annular member having a circular or otherwiseround cross section.
 4. The valve of claim 1, wherein the direction ofmovement of the blocking element is substantially rectangular to anextension of the passage.
 5. The valve of claim 1, wherein the plane inwhich the valve seat is located extends under an acute angle ofinclination of the valve seat to the extension of the passage.
 6. Thevalve of claim 1, wherein the plane in which the annular member islocated extends under an acute angle of inclination of the annularmember to the extension of the passage.
 7. The valve of claim 6, whereinthe angle of inclination of the annular member is between 30° and 60°,in particular between 40° and 50°, and preferably substantially about45°.
 8. The valve of claim 1, wherein the blocking element is a pointed,blunt or beveled cone, and the imaginary annular member is an ellipticring with a circular cross section, the imaginary annular member beinginclined such with respect to the direction of movement of the blockingelement that it encloses a circular area, seen in the direction ofmovement of the blocking element.
 9. The valve of claim 1, wherein thevalve seat is an integral part of the valve housing.
 10. The valve ofclaim 1, wherein the valve housing is a T-pipe with a substantiallystraight passage pipe portion and a branch pipe portion substantiallyrectangular to the same, and that the passage pipe portion is providedwith an inward protruding continuous annular surface section situated ina plane inclined under an angle of 45° to the longitudinal axis of boththe passage pipe portion and the branch pipe portion and on whichsurface section the valve sealing surface lies, the spherical surfacesection extending along one of the two corner portions between thepassage pipe portion and the branch pipe portion.
 11. The valve of claim10, wherein the spherical surface section is formed by locally deformingthe T-pipe in a bead-like manner.
 12. The valve of claim 1,characterized in that the valve housing is made of plastics material.13. The valve of claim 1, characterized in that the valve housing is aninjection molded part.
 14. The valve of claim 1, characterized in thatthe valve housing is formed by a non-cutting forming of a pipe piece.